Events & Seminars

2020 Oct 28

Analysis seminar: Hans Knüpfer (Heidelberg) — Γ-limit for zigzag domain walls in thin ferromagnetic films

12:00pm to 1:00pm

Charged domain walls are a type of transition layers in thin ferromagnetic films which appear due to global topological constraints. The underlying micromagnetic energy is determined by a competition between a diffuse interface energy and the long-range magnetostatic interaction. The underlying model is non-convex and vectorial. In the macroscopic limit we show that the energy Γ-converges to a limit model where jump discontinuities of the magnetization are penalized anisotropically. In particular, we identify a supercritical regime which allows for tangential variation of the domain walls.
2020 Oct 25

Kazhdan seminar: Tomer Schank "Sheaves with nilpotent support"

Repeats every week every Sunday until Sun Jan 17 2021 .
2:00pm to 4:00pm

Abstract: Given a smooth and proper curve X and a reductive group G one can consider the stack Bun_{G,X} of principal G-bundles on X. This stack has an important role in Algebraic Geometry and Representation Theory especially with regard to the Langlands program. We shall study the geometry of Bun_{G,X} and the category 
D(G,X) of constructible  sheaves on Bun_{G,X}. We shall be especially interested in the subcategory D_{nil}(G,X) of sheaves with nilpotent singular support.
2020 Oct 25

Kazhdan seminar: Yoel Groman and Jake Solomon "Stability conditions"

Repeats every week every Sunday, 52 times .
4:00pm to 6:00pm

Abstract: We will discuss stability conditions on triangulated categories following the work of Douglas and Bridgeland. Concrete examples of stability conditions will be given from symplectic and algebraic geometry, which will also illustrate mirror symmetry. An effort will be made to give a gentle introduction to the relevant background material from category theory, symplectic geometry and algebraic geometry.
2020 Oct 25

Kazhdan seminar : Ari Shnidman "Fundamental lemmas and Fourier transform"

Repeats every week every Sunday until Sun Jan 17 2021 .
11:00am to 1:00pm

Abstract: A fundamental lemma is an identity relating p-adic integrals on two different groups. These pretty identities fit into a larger story of trace formulas and special values of L-functions.  Our goal is to present recent work of Beuzart-Plessis on the Jacquet-Rallis fundamental lemma, comparing integrals on GL(n) and U(n).